1. Field of the Invention
This invention relates generally to systems for verifying quality control, and more particularly, to a system that ensures that a part or assembly is pressed to depth within a predetermined tolerance and measurement accuracy, and that determines the quality of the interference fit.
2. Description of the Related Art
In current pressing applications it is difficult or impossible to determine whether a pressed-in part has been pressed to a fully seated condition when the operation is complete. Current systems endeavor to ensure that a pressed-in part is fully seated by monitoring the press force and continuing the operation until a predetermined amount of force is applied. This predetermined amount of force is assumed to insure that the pressed part is driven to a full seating position, and that the force applied is representative of the quality of the interference fit. These assumptions, however, are not always correct. The force required to overcome the interference fit in the pressing operation oftentimes exceeds the preset force limit of this known approach. Sometimes, a particle of dirt or metal will become lodged behind the part that is being pressed, causing a false reading on the press force. Thus, the application of the full measure of the predetermined force will not always result in complete inward displacement and seating of the part desired to be pressed into place.
A second current method of verifying press quality is to measure the depth of press at the press ram head. Unfortunately due to part and casting variations this simple single-measurement system is inadequate, as it will not identify the quality of a precision pressing operation.
In the case of a valve seat in an engine head, or a bearing cup in an assembly, the normal working forces, vibration, and heat of the product will finally seat the incorrectly assembled part during the engine or component's normal working life. This form of seating action, however, will generally cause changes in the running clearances of the assembly that are critical to the product's over all life or performance.
In addition to the foregoing, valve seats in particular are subjected to tremendous amounts of heat from exhaust gasses. Oftentimes, the temperature of the exhaust gas approaches the melting point of some metals. It is essential that proper seating of the valve seat within the receiving pocket be effected to promote transference of the heat to the cylinder head casting, which contains the cooling water jackets.
There is a need, therefore, for a quality monitoring system that overcomes the foregoing problems.
It is, therefore, an object of this invention to provide a system for pressing-in a press-fit part, such as a valve seat or bearing cup, into a receiving pocket in a receiving assembly, such as a cylinder head, that achieves seating of the part to a predetermined depth reliably.
It is another object of this invention to provide a system for pressing-in a press-fit part to achieve seating within predetermined tolerances without applying excessive continuous insertion force.
It is also an object of this invention to provide a self-aligning press fit ram.
It is a further object of this invention to provide a system for pressing-in a press-fit part to achieve verified seating within predetermined tolerances.
It is additionally an object of this invention to provide a system for pressing-in a press-fit part, such as a valve seat or bearing cup, into a receiving pocket in a receiving assembly, such as a cylinder head, that achieves seating of the part to a predetermined depth reliably, notwithstanding variations in dimensions of the press-fit part.
It is yet a further object of this invention to provide a system for pressing-in a press-fit part, such as a valve seat or bearing cup, into a receiving pocket in a receiving assembly, such as a cylinder head, that achieves seating of the part to a predetermined depth reliably, notwithstanding variations in depth of the receiving pocket.
It is also another object of this invention to provide a system for pressing-in a press-fit part into a receiving pocket in a receiving assembly wherein the insertion force is monitored.